K181 rebuild

[Gregor 4,838]

I didn't want to start this project yet, as I have 2 other projects going on already, but I'm waiting on parts. Waiting on parts is the worst.

 

I tore down the K 181 I don't have a spec # as the plate was missing. Measuring the bore at 2.9325" and the stroke at 2.75", I have determined it to be a K-181, 8HP. I hope that's right. The inside looks very good.The piston has some of what I believe to be carbon scarring on the top. It has no markings of being .010" or .020 over, and it measures 2.9295" on the skirt. Keep in mind, all these measurements are being done with my $59.95 digital caliper. Not $500 Starett tools. I have not got my bore gauges out yet, not sure if there is a reason to. Not sure there is a reason for me to even have bore gauges, but they looked cool. The piston does have some very light scratches on on one side of the skirt,

but all internals being replaced anyway. This connecting rod came complete with oil dipper, unlike my 7HP, which had somehow disappeared. The rod journal also measures with in spec. There is a snug .007" end play in cam shaft. I cannot see any shims on it. Doesn't mean they aren't there, but I cannot see them. I asked my wife to look. "What's a shim?"  Just go away...... I wanted to remove the cam shaft on this build, but it does not seem to want to be removed. At least not with the hammer and punch I was using.The head cleaned up well, with a wire brush in my drill, and some sand paper on a flat surface. I know it needs more yet.I would like to remove the exhaust pipe, but it too doesn't seem to want to be removed. I would also,like to remove the oil fill tube, but I am not sure how. Is it threaded in? Pressed in? Should I leave it for the machine shop to do? I want to take the block and crank to the shop, have them check it, and do what they think is necessary. But I'm kind of afraid they will run the gammit on it, necessary or not. It is how they make their money. If someone can convince me to get out a bigger hammer and punch, and remove the cam shaft, I will. Maybe that's another thing best left to the machine shop.

BTW  I have a crack at yet another K-181. Someday I am going to have to find enough rollers to put all these motors on, and then build another garage.

[oliver2-44 8,852]

I'll let the experts chime in on removing that camshaft.  I disassemble a rusty, rod ventilated parts engine as I wanted the camshaft and crank for another block.  The flange on the inside of the block supporting the camshaft split when the cam finally moved.  So for my 2 cents i would go easy on the camshaft.  You don't get an accurate bore measurement with a set of calipers as there is a tiny distance at the top of the block that the rings don't ride on/wear.  You might not 'feel" a ridge, but there's a tiny one there. Also, you may want to flatten that head and remove those scratches using some wet/dry sandpaper on a piece of glass.  

[953 nut 51,656]

Take a few minutes to read through this tutorial done by @prondzy, it it excellent. The machine shop can R&R the cam, governor and bearings for you if you aren't comfortable doing them.

 

[The Tuul Crib 7,332]

That pin going through the camshaft can be a booger to get out sometimes. I've used a punch and a hammer and come out very easily and I've also used my press to get it out. When you put it back together what I would do is put the shaft in the freezer for a couple of days and then it will go in a lot easier.

[Gregor 4,838]

1 hour ago, 953 nut said:

Take a few minutes to read through this tutorial done by @prondzy, it it excellent.

 

That was a great read. I read it back in December, but  it's amazing how much a guy forgets, when he isn't doing something like this all the time. Thanks for the reminder.

 

As far as the cam goes, I'm not sure what I am going to do. I am a big believer in, "If it aint broke, don't fix it" The downside is, I cannot replace the bearing on that side, without removing the cam.That being said, I have never liked hammering on bearings anyway.

[ebinmaine 63,114]

Do you have multiple machine shops available?

If you don't trust that the one you have nearby won't treat you fairly... DON'T BRING ANYTHING THERE. 

You're better off sending it out to a place someone here is familiar with. 

 

Seems to me if it's commonplace to remove the cam during a rebuild you should have the shop do that when they check the block over. 

 

[Achto 26,548]

The oil tube I believe is just pressed in with an o-ring seal.

 

I can't get a good look at the exhaust in your pictures. Is it bolted to the block with 2 bolts, or is it threaded into the block? If it is a piece of pipe threaded into the block, I have carefully taken a sawzall to cut a slit length wise in the pipe so that it can be split for removal. Cut for a bit, check your depth. Keep repeating this method until you can faintly see the threads showing through in the bottom of your cut. Try not to cut into the threads. At this point the pipe should break and collapse when you put a pipe wrench on it to remove it. Once it collapses it will thread out easily.

Edited March 10, 2021 by Achto

[lynnmor 6,775]

You should be applying penetrating oil to the exhaust, oil fill and all fasteners several times a day for as many days as you have.

[Gregor 4,838]

The exhaust was a 1" 90, screwed into the block. With a little map gas heat, a hammer, and a 20" pipe wrench, it's history. The threads in the block don't look great. I may have to have a plumber friend stop by with a 1" tap, and clean them up a bit.

A larger hammer convinced the cam shaft pin to come out. If all else fails, grab a bigger hammer! There was in fact a shim. I have it zip tied to my cam as @prondzysuggested in his tutorial, so as not to forget it.

In the Kohler manual, disassembly section, page 10.5, it says,This has me a bit confused. There is a 1 1/8" plug in the block, on the PTO side, but I see no reason to remove it, or a good way to do it. Any direction here anyone?

The oil fill tube was in fact pressed in. I fashioned me a tool from a 3/8" bolt, some washers, and a steel collar, and it came right out, no problem. I thought I was going to have to drill a hole in my table top, if I wanted to set this motor on it's top. Disaster avoided.

The crank shaft bearing also came out easier than expected. Not like what I am use to on a bearing that size.

So now I have a completely bare block, except for that plug. It's going off to the machine shop.

I have not rebuilt many 4 cycles, lots of 2 cycles but not 4. I think @prondzyalso mentioned this in his post, but it bears repeating. Before removing the pan bolts, and tapping it lose with your hammer, DRAIN THE OIL FIRST ! This isn't a problem with 2 cycles, and it just skipped my mind. It makes a He!! of a mess.

[Gregor 4,838]

@prondzyWhat if anything can you tell me about that cup plug? I get the idea that there was suppose to be a plug over the end of the cam shaft pin. On mine, there was not. One end of the pin is slightly larger, so it's a very tight fir when you get it that far, but there was no plug.

[Mickwhitt 4,144]

Greg.   There was no plug on my K301 can shaft but I put anew one in when I rebuilt the engine.

Look for pressed steel expansion plugs. Its a half inch diameter one for the cam shaft.

It only knocks out one way remember.

Mick 

[Mickwhitt 4,144]

This is the expansion plug knocked in to the bearing plate side of the crank case camshaft pin hole. 

Mick 

[pfrederi 17,147]

The bearing plate end has a looser fit on the cam shaft rod....  Cap may keep out dirt  Crank case end is tight...

[prondzy 3,867]

7 hours ago, Gregor said:

@prondzyWhat if anything can you tell me about that cup plug? I get the idea that there was suppose to be a plug over the end of the cam shaft pin. On mine, there was not. One end of the pin is slightly larger, so it's a very tight fir when you get it that far, but there was no plug.

Never seen one with a plug. Just install the cam pin in so

it sits slightly below the block face on the pto side 

[Gregor 4,838]

I took the block and crank to the machine shop this morning. I hope I get mine back as fast as @Mickwhittgot his, but I have my doubts. I can't order anything until I see what they say. All the measurements I took were well within spec. I am curious to find out what they measure.

[Mickwhitt 4,144]

I was with the engineer when he measured my engine.

He checked the crank journal to make sure a 10 thou undersize con rod would be ok.

Then just measured the bore to see what oversize piston was needed. The wear meant he was happier with a 20 thou oversize piston. 

Mick

[Mickwhitt 4,144]

17 hours ago, pfrederi said:

The bearing plate end has a looser fit on the cam shaft rod....  Cap may keep out dirt  Crank case end is tight..

This looks right, the cam pin only goes in from one side of the crank case so the cup keeps muck out and oil in. 

There is a dimension for the pin inset into the hole I believe.

Mick 

[Gregor 4,838]

While the block and crank are at the shop, I am cleaning and evaluating other parts to see what I might need for the rebuild. The head cleaned up well. I think it would be nearly impossible to get every little mark and bit of discoloration out of it, but it looks good to me. 400 wet, then 600 wet, then 1000 wet, on a granite tile. I went around it with a .002" feeler gauge, and could not get in anywhere.

I disassembled, cleaned and serviced the starter. It  spins better than it did, but I am not hopeful. I don't think it will have the poop to crank a motor, but we'll see. The carb is as many pieces as I could make of it, and is soaking in Berryman for a couple of days, as suggested by a couple of other members. It is in rough shape, but I got a spare China carb with the motor, I can use if I have to. ( to or too?, I always get confused on that) I have a pile of tin work and the flywheel ready to go to the media blaster. I am thinking of removing some tin work off the 876 motor and taking it along, as the blast shop has an $85 minimum shop charge. I may as well get my moneys worth.

Now the big question. The rebuild kit. I see that Kevin on ebay offers 3 different kits. Each a different price, and each with difrent bits and pieces. All kits have the basics. One kit includes a new exhaust vale. Another offers a new (I assume) China carb. I think they all offer chrome rings. All these kits are considerably less money than the kit from isavetractors. Their kit offers the basics, plus both valves, new carb, and new coil. While their kit does of course have rings, it doesn't mention "chrome" rings. One thing I do like about isavetractors. If I have a question, or there is a problem, I can call and talk to to someone. Many times Norman himself. I have had great service from them in the past. With Kevin, apparently communication is through ebay messaging and email. I believe @Mickwhittwas satisfied with the kit he got from Kevin. Has anyone else ever dealt with isavetractors? Are chrome rings a significant improvement? Are the 2 valves, carb and coil worth the $85 difference between Kevins best kit and Normans best kit? Opinions?  Thanks  Greg

[Gregor 4,838]

So again, more questions.This is a pic from the stator/coil from the K 181. Looking through the Kohler manual, I don't see this configuration at all, in their electrical section.  The wires indicated by the red arrow, were wadded up, taped up, and stuffed behind the bearing plate. I assume they at one time went to the points and condenser. The wire indicated by the black arrow is of course the high tension lead, (spark plug) wire, and was cut off. There is no continuity at all, between the 2. There is also no continuity between the spark plug wire and ground. There is infinite continuity between the points wire and ground. .000 on my meter. The blue wire simply goes through the loom, connects to nothing. 2 black wires from the stator go to the plug, indicated by the yellow arrow. I assume these are the AC volt charging wires that went to a regulator of some sort. There is infinite (.000) continuity between them, no continuity to ground. The wire indicated by the white arrow comes from the top of the plug. I assume it went to the battery circuit for charging.

I don't have a spec number on this motor. It does however have green tin work on it, indicating it came from John Deere, but as far as which model, I have no idea. The only John Deeres I can find on Tractordata.com that had an 8HP Kohler , are the 110, 200, and 208. They all had 12V batteries with electric start.

My question is; could this motor have been switched to battery ignition, or can it be? Or can it be converted to electronic ignition? Any help?

[pfrederi 17,147]

Looks like a very common Magneto 10 amp stator.

 

Maybe mag failed and someone cut the pug wire and went to a battery points system.  That stator wouldn't operate a breaker less ignition

 

 

[Gregor 4,838]

It just amaze me how you guys can come up with all these diagrams and schematics and such. I search and search, and can't come up with anything. Maybe I should take a break from motors and tractors, and take a course on computers first. It's just aggravating.

[pfrederi 17,147]

If you are working on a K-181 you should download the parts manual.  Faster and easier to access than going to the Kohler site an looking up your engine/spec#

[Gregor 4,838]

No offense meant, so PLEASE don't take it that way, but...telling me to download the parts manual, is like me telling you to take the turret clutch of a Brunswick bowling machine. I have done it thousands of times. Chances are, you would not have a clue. That's just how good I am with computers.

[pfrederi 17,147]

Go to the manuals section here on red square look at the engine section then Kohler  Search that section for K181 make sure you check the search this category block.

[Gregor 4,838]

Thank You. It took a while, but I found it. I downloaded (I guess) and printed every word I could find concerning a K 181, and a couple of others. At least the ones I could open. Some, I could not.

Books in my cupboard I can find. Files, not so much. again.

 

It will not let me open this. Engine Kohler Magneto ignition coil with points and condenser 47 755 20-S.jpg 1.0.0

Edited March 12, 2021 by Gregor